<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
		<style type="text/css">
			.box1{
				width: 2000px;
				height: 100px;
				background: red;
			}
			.box2{
				width: 200px;
				height: 200px;
				background: green;
				position: absolute;
				right: 0;
				bottom: 0;
			}
			.box3{
				width: 50px;
				height: 2000px;
				background: blue;
			}
			
			.bigbox{
				width: 300px;
				height: 300px;
				background: red;
				border: 10px solid black;
				position: absolute;
				padding-top: 50px;
				padding-left: 50px;
				/* padding-right: 20px;
				padding-bottom: 20px; */
			}
			.smallbox{
				width: 100px;
				height: 100px;
				background: green;
				position: absolute;
				top: 0px;
				left: 0px;
				/* bottom: 0;
				right: 0; */
			}
		</style>
	</head>
	<body>
		<!-- 
		注意点
		1.如果一个绝对定位的元素是以body作为参考点, 那么其实是以网页首屏的宽度和高度作为参考点, 而不是以整个网页的宽度和高度作为参考点
		2.一个绝对定位的元素会忽略祖先元素的padding		 
		 -->
		 <div class="box1"></div>
		 <div class="box2"></div>
		 <div class="box3"></div>
		 
		 <!-- <div class="bigbox">
		 	<div class="smallbox"></div>
		 </div> -->
	</body>
</html>
